Circuit arrangement for the transmission of ultra high frequency electrical oscillations



PH 4r, i950 J. M. VAN HOFWEEGEN ETAL 2,502,766

cIRcuIT ARRANGEMENT RoR THE TRANSMISSION oF ULTRA HIGH FREQUENCYELECTRICAL OSCILLATIONS Filed July 2o, 194e AGEN Patented pr. 4, Q

CIRCUIT ARRANGEMENT `FOR. THE TRANS- MISSION OF ULTRA HIGH FREQUENCYELECTRICAL OSCILLATIONS Johannes Marinusvan Hofweegen and Kornelis SwierKnol, Eindhoven, Netherlands, assignors to Hartford National Bank andTrust Coinfi pany, Hartford, Conn., as trustee Application July 20,1946, Serial No. 685,188 In the N etherlandsJune 1, 1945 Section 1,Public Law 690, August 8, 1946 Patent expires June 1, 1965 Claims.

for the transmission of ultrahigh frequency electrical oscillations.

In transmitting ultrahigh-frequency electrical oscillations use is oftenmade of circuits by means of which a definite impedance is transformedinto an arbitrary or other impedance (impedance transformers) forinstance where the impedance of an apparatus consumingultrahigh-frequency electrical oscillations is to be matched to thesource of energy. Furthermore it is often desirable, for instance formeasuring purposes, to have very small, variable capacities andinductances whose values are exactly known. In these cases use maylikewise be made with advantage of an impedance transformer, animpedance which is several times too large or too small then beingconnected to one side of the transformer, whereas the desired smaller orlarger impedance is found at the other side of the impedancetransformer.

Impedance transformers are known, consisting of a certain number ofparallel conductors which form lecher systems in pairs that are eachadjusted by means of a short-circuit bridge and are decoupled withrespect to one another. These impedance transformers are suffering fromthe drawback that their construction and control is complicated.

The present invention provides a simple circuit by means of which anyimpedance can be transformed into any other impedance and the adjustmentof which is easy.

The circuit according to the invention is characterised by threeparallel or substantially parallel conductors a, b, c, all of which areintercoupled and of which two of the ends at the same side serve toconstitute input terminals a, c whereas the third of these ends,together with one of the said ends, serve as output terminals b, c ofthe circuit, the circuit comprising two, preferably movable,short-circuit bridges one of which interconnects the conductors a and band the other interconnecting all of the three conductors.

In an extremely suitable form of construction of the circuit theconductor c, to which is connected the terminal common to the input andthe output of the circuit, surrounds the two other conductors a and b.

In order that the invention may be more clearly understood and readilycarried into effect it will now be described more fully with referenceto the accompanying drawing, given by way of example, which representsthe said very suitable form of construction of the circuit (impedancetransformer) according to the invention. Figure 1 is (ci. irs- 44) 2 alongitudinal section and Figure 2 a cross-section of the impedancetransformer. The impedance transformer consists of three parallelconductors a, b and c. [The conductor c is tubular and surrounds theconductors a and b. The left-hand end of the conductors act as inputterminals A and C and output terminals B and C of the circuitrespectively. Between the conductors a and b is provided a movableshort-circuit bridge K1 and furthermore a movable short-circuit bridgeK2 interconnects the conductors a, b and c. If-as shown in Figure l-animpedance Z2 is provided between the terminals C and B, an impedance Z1is measured between the terminals A a-nd B.

The said impedance transformer has the property that any impedance Z2can be transformed into any other impedance Z1 by a suitable adjustmentof the short-circuit bridges K1 and K2, consequently by controlling oradjusting only two variable values. With the known impedancetransformers the various conductors form pairs of lecher systems whichare separated from each other and each of which must be adjusted bymeans of a short-circuit bridge. However, these impedance transformers,at least insofar as they are capable, similarly to the presenttransformer, of transforming some impedance into any other impedance,are much more complicated in regard to construction and operation, sincethere are at least three lecher systems so that three short circuitbridges must be adjusted.

The impedance transformer according to the invention is based on therecognition that by intercoupling the various lecher systems and byproviding the short-circuit bridges in the manner referred to, theadjustment of the impedance transformer can be greatly simplifiedwithout the aforesaid property (the possibility of transforming someimpedance into any other impedance) being lost.

What we claim is:

1. A circuit arrangement for transmitting ultra-high-frequencyelectrical oscillations, which comprises three substantially parallelconductors a, b, c, all of which are intercoupled and of which two ofthe ends at the same side serve to constitute input terminals a, cwhereas the third of these ends, together with one of the said ends,serve as output terminals b, c of the circuit, the circuit comprisingtwo, movable, short-circuit bridges one of which interconnects theconductors a and b and the other interconnecting all of the threeconductors.

2. A circuit arrangement as claimed in claim l, in which the conductorc, to which is connected conductors, a pair of output terminalsconnected to said end of said rst conductor 'andthe corresponding end ofsaid third conductor, a rst shorting member interconnectingcorresponding points on said rst, second and third conductors, and asecond snorting member interconnecting corresponding points on saidsecond and third conductors.

4. An ultra-high-frequency impedance transformation device comprisingrst, second and third conductors arranged in parallel relation, a, pairof input terminals connected to correisponding ends of said rst andsecond conduc- 'tors,a pair of output terminals connected to said end ofsaid lfirst conductor and the corresponding end of said third conductor,a first movable :bridge interconnecting said rst, second and thirdconductors, and a second movable bridge interconnecting said second andthird conduc- Itors.

5. An ultra-high-frequency impedance trans- .formation device comprising-first, second and third conductors arranged in parallel relation. apair of input terminals connected to correspondingr ends of said firstand second conductors, apair of output terminals connected to said endof said first conductor and the corresponding end of said thirdconductor, said rst conductor being tubular and surrounding saidsecond'and third conductors, a first movable bridge disposed within saidrst conductor and interconnecting-al1 of said conductors, and a secondmovable shorting bridge disposed within said rst conductor andinterconnecting said second and third conductors.

JOHANNES MARINUS VAN HOFWEEGEN.

KORNELIS SWIER KNOL.

REFERENCES CITED The following references are of record in the file o'f`this patent:

FOREIGN PATENTS Number Country Date 435,153 Great Britain Sept. 16, 1935802,881 France June 22, 1936 647,149 Germany June 30, 1937

